The subject matter disclosed herein generally relates to seals used in conjunction with gas turbine engines and, more particularly, to fire seals such as turkey feather seals.
Regulatory requirements for modern aircraft require the containment of a fire within a power plant installation. For instance, if a fire is present in the engine compartment surrounding the gas turbine engine, the structures defining the engine compartment must meet certain standards related to flame resistance and fire containment. In order to meet requirements relating to fire containment, fire seals are typically used between separate adjacent components defining the engine compartment to seal between them and prevent the spread of fire. The fire seals resist the flames and the environment of the fire, and will contain the fire by not allowing the flames to pass through.
One known fire seal arrangement is called a “turkey feather” fire seal. The turkey feather seal consists of two adjacent pieces of thin metal, usually having a degree of flexibility, with segmented fingers that overlap one another. The segmented fingers help allow the turkey feather fire seal to compress against a sealing surface. The segmented fingers also help the seal to bend in multiple planes in order to fit it into a location with complex geometry. Owing to these advantages, a turkey feather seal is often used between thrust reverser modules that are supported on an aircraft propulsion system and hinge to an open position. A turkey feather seal mounted to the thrust reverser module will contact and compress against a complexly shaped surface on the engine or other structure when the module is hinged closed, and form an effective fire seal. The turkey feather seal provides a solid barrier so that flame cannot pass to downstream locations.
While the traditional turkey feature seal effectively prevents the passage of flames and spread of fire, it also blocks airflow between the two components it is sealing between. Air flow in an engine compartment is used for cooling purposes. Without air flow through a seal, the air in its vicinity may not be exchanged as frequently as desired and may become very hot. High temperatures within an engine compartment can degrade components and structures. High temperatures might even degrade a turkey feather seal and anneal it to an extent that it loses its spring and seals less effectively.